Culture and science
The search for alien signals and technology, from Project Ozma to Oumuamua and 3I/ATLAS. 22 events, newest first.
Select any year above to see what happened that year.
Open Interstellar objects and SETI as a timeline
Government19 Dec 2025
Interstellar comet 3I/ATLAS came no closer to Earth than about 270 million km (1.8 AU), on Dec. 19, 2025, per NASA, posing no danger. Astrophysicist Avi Loeb kept pointing to anomalies, while NASA treated it as a natural comet.
Photo: NASA, ESA, STScI, D. Jewitt (UCLA), M.-T. Hui, Public domain
Government27 Nov 2025
The International Asteroid Warning Network opened an observing campaign on 3I/ATLAS to practise measuring precise positions of fuzzy comets, running to Jan. 27, 2026. Some outlets cast it as a secret planetary-defense drill; the network described it as a routine astrometry exercise.
Photo: International Gemini Observatory/NOIRLab/NSF/AURA/B. Bolin, CC BY 4.0
Government19 Nov 2025
After a shutdown delay, NASA held an online briefing releasing 3I/ATLAS images from about a dozen missions. Associate Administrator Nicky Fox said it behaves like a comet and that NASA saw no technosignatures, answering speculation that it was an alien craft.
Photo: NASA, ESA, D. Jewitt (UCLA); Image Processing: J. DePasquale (STScI), CC BY 4.0
Government3 Oct 2025
As 3I/ATLAS passed about 30 million km from Mars on Oct. 3, 2025, ESA's ExoMars Trace Gas Orbiter imaged its coma, and NASA's Mars Reconnaissance Orbiter, MAVEN and Perseverance also observed it, showing a fuzzy comet.
Photo: NASA/JPL-Caltech/University of Arizona, Public domain
Media6 Aug 2025
Omer Eldadi, Gershon Tenenbaum and Avi Loeb posted a 0-10 scale for rating how anomalous an interstellar object is, from natural (0) to confirmed artificial (8-10). They rated 'Oumuamua and 3I/ATLAS a 4; Loeb has said 3I/ATLAS is most likely a natural comet.
Photo: Christopher Michel, CC BY-SA 4.0
Media16 Jul 2025
Weeks after the interstellar object 3I/ATLAS was found, Avi Loeb and two co-authors posted a non-peer-reviewed paper asking whether it could be alien technology. NASA describes it as a comet, and astronomers quoted in the press said the evidence points to a natural object.
Photo: International Gemini Observatory/NOIRLab/NSF/AURA/B. Bolin, CC BY 4.0
Government1 Jul 2025
The NASA-funded ATLAS survey telescope in Rio Hurtado, Chile, found a fast object on an interstellar path, reported to the Minor Planet Center on July 1, 2025. Named 3I/ATLAS, it was only the third known interstellar visitor and was classified as a comet.
Photo: International Gemini Observatory/NOIRLab/NSF/AURA/K. Meech, CC BY 4.0
MediaMar 2024
Johns Hopkins seismologist Benjamin Fernando's team told the Lunar and Planetary Science Conference that the Manus Island seismic signal Avi Loeb's group used to find the 2014 fireball changed direction along a road, likely a passing truck. Loeb disputed the coverage.
Photo: Avi Loeb and Frank Laukien (study authors), CC BY 4.0
MediaJun 2023
Harvard's Avi Loeb led a June 2023 search off Papua New Guinea for fragments of the 2014 fireball IM1, recovering tiny metal spherules he said might be interstellar or even technological. Other scientists disputed it, attributing the material to coal ash and the seismic trace to a passing truck.
Photo: NASA, Public domain
Media2023
Harvard astrophysicist Avi Loeb published 'Interstellar' (HarperCollins), a popular book following his earlier 'Extraterrestrial' and tied to his search for interstellar objects and possible alien technology.
Photo: Aviloeb, CC BY-SA 4.0
Media14 Jun 2022
Science and Technology Daily, a state-run paper, reported that a Beijing Normal University team had found suspicious narrow-band signals in FAST data; the report was then removed. Lead scientist Zhang Tongjie said radio interference was a very likely cause.
Photo: SCJiang, CC BY-SA 4.0
MilitaryApr 2022
U.S. Space Command officials confirmed the velocity data for a January 2014 fireball off Papua New Guinea that Harvard researchers had argued came from outside the solar system. NASA noted the short data record makes the interstellar origin hard to confirm.
Photo: Abraham Loeb and Frank H. Laukien (Galileo Project), CC BY 4.0
Close encounters26 Jul 2021
Harvard astronomer Avi Loeb announced the Galileo Project, a privately funded effort to search systematically for evidence of extraterrestrial technological objects, including UAP and interstellar visitors, using purpose-built instruments and publishing data openly.
Photo: Christopher Michel, CC BY-SA 4.0
Media26 Jan 2021
Harvard astronomer Avi Loeb's book argued that the interstellar object 'Oumuamua could be an artifact of another civilization. Reviewers called it provocative, but many scientists were unconvinced, noting the object can no longer be observed to test the idea.
Photo: Christopher Michel, CC BY-SA 4.0
Media12 Nov 2018
Harvard astronomers Shmuel Bialy and Avi Loeb argued in a peer-reviewed letter that sunlight pressure could explain the first known interstellar object's odd acceleration if it were a very thin sheet, raising the possibility of an artificial light sail. Most astronomers favored natural explanations.
Photo: Alan Fitzsimmons (Queen's University Belfast), Isaac Newton Group, Public domain
Media13 Dec 2017
The Breakthrough Listen project pointed West Virginia's Green Bank Telescope at 'Oumuamua, the first known interstellar object, across four radio bands. Its initial results found no sign of artificial signals, though most of the data was still being analyzed.
Photo: NRAO/AUI/NSF, CC BY 4.0
Government25 Sep 2016
China's state news agency Xinhua reported the opening of the 500-meter FAST radio telescope in Guizhou, then the world's largest single-dish radio telescope. Chinese astronomers said its work would include studying possible interstellar communication signals.
Photo: NASA/METI/AIST/Japan Space Systems, and U.S./Japan ASTER Science Team, Public domain
Media11 Jul 1997
Warner Bros. released Contact, Robert Zemeckis's adaptation of Carl Sagan's novel, starring Jodie Foster as a radio astronomer who detects a signal from the star Vega. It framed alien contact through radio searches rather than saucers.
Photo: NASA, Public domain
Media1996
David Twohy's The Arrival starred Charlie Sheen as a SETI radio astronomer who detects an alien signal, is fired, and uncovers aliens disguised as humans who are secretly warming Earth. It was overshadowed by Independence Day, released soon after.
Photo: Angela George, CC BY-SA 3.0
Government1985
Physicist Harold Puthoff founded the Institute for Advanced Studies at Austin, a lab studying the quantum vacuum, gravity and interstellar flight science in relation to space propulsion and energy. It was incorporated under EarthTech International in 1991.
Media1974
At a ceremony marking an upgrade of the Arecibo radio telescope in Puerto Rico, scientists beamed a short pictorial radio message toward the globular cluster M13, about 21,000 light-years away. The SETI Institute notes a reply is unlikely ever to come.
Photo: Arne Nordmann ( norro ), CC BY-SA 3.0
GovernmentApr 1960
Radio astronomer Frank Drake used an 85-foot dish at the National Radio Astronomy Observatory to listen near 1420 MHz for signals from Tau Ceti and Epsilon Eridani from April to July 1960. Nothing artificial was found; it began scientific SETI.
Photo: NRAO/AUI/NSF, CC BY 4.0
